class_docstr: Custom sphinx-gallery scraper to save the current Canvas to an image.
code: def _frame_exports_to_list(self, frame_specifier):
      frames = frame_specifier.split(" ")
      frame_paths = []
      for frame_fn in frames:
          # existing image file created by the example
          if not os.path.isfile(frame_fn):
              raise FileNotFoundError(
                  "Example gallery frame specifier must be a frame number, "
                  "frame range, or relative filename produced by the example."
              )
          frame_paths.append(frame_fn)
      return frame_paths
  
imports: from __future__ import annotations
  import os
  import time
  import shutil
  from vispy.io import imsave
  from vispy.gloo.util import _screenshot
  from vispy.scene import SceneCanvas
  from sphinx_gallery.scrapers import optipng, figure_rst
label_desc: Use image node_id 6 for calling the VisPyGalleryScraper obj's underlying member method code with example usage: obj._frame_exports_to_list(frame_specifier) and returns: frame_paths